Q: How do I earn decorated weapons by playing the game?
A: Weapon drops are awarded for play time over the course of a week. As your play time increases, the drop rate will slow down. The drop rate will reset when the week rolls over.

Q: How do I earn decorated weapons by playing the game?
A: Weapon drops are awarded for play time over the course of a week. As your play time increases, the drop rate will slow down. The drop rate will reset when the week rolls over.

Arms Deal FAQ source.

ya, that doesn't say anywhere it's the same reset for everybody...
as the poster above said his is different, just like mine.